Composition for etching and method for manufacturing semiconductor device using same

ABSTRACT

A composition for etching and a method of manufacturing a semiconductor device, the method including an etching process of using the composition for etching, are provided. The composition for etching includes a first inorganic acid; any one first additive selected from the group consisting of phosphorous acid, an organic phosphite, a hypophosphite, and mixtures thereof; and a solvent. The composition for etching is a high-selectivity composition for etching that can selectively remove a nitride film while minimizing the etch rate for an oxide film and does not have a problem such as particle generation, which adversely affects device characteristics.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is continuation application of U.S. patent applicationSer. No. 15/71,471, which is a National Stage Patent Application of PCTInternational Patent Application No. PCT/KR2016/012215 (filed on Oct.28, 2016) under 35 U.S.C. § 371, which claims priority to Korean PatentApplication Nos. 10-2015-0172472 (filed on Dec. 4, 2015),10-2015-0178772 (filed on Dec. 15, 2015), 10-2015-0178774 (filed on Dec.15, 2015), 10-2015-0178775 (filed on Dec. 15, 2015), 10-2015-0178776(filed on Dec. 15, 2015), 10-2015-0178777 (filed on Dec. 15, 2015), and10-2015-0178778 (filed on Dec. 15, 2015), the teachings of which areincorporated herein in their entireties by reference.

TECHNICAL FIELD

The present invention relates to a composition for etching, and moreparticularly, to a high-selectivity composition for etching capable ofselectively removing a nitride film while minimizing the etching ratefor an oxide film, and to a method of manufacturing a semiconductorelement, the method including an etching process of using thiscomposition for etching.

BACKGROUND ART

In semiconductor manufacturing processes, oxide films such as a siliconoxide film (SiO₂) and nitride films such as a silicon nitride film(SiN_(x)) are representative insulating films, and these films are usedeach independently, or one or more layers are used in an alternatelylaminated form. Furthermore, these oxide films and nitride films arealso used as hard masks for forming electroconductive patterns such asmetal wiring.

In a wet etching process for removing a nitride film, a mixture ofphosphoric acid and deionized water is generally used. The deionizedwater is added in order to prevent a decrease in the etch rate and avariation in the etch selectivity for oxide films; however, there is aproblem that even a small change in the amount of deionized watersupplied may cause defects in a process for removing a nitride film byetching. Furthermore, phosphoric acid is a strong acid showingcorrosiveness, and handling of this acid is difficult.

In order to solve these problems, technologies for removing a nitridefilm by using a composition for etching including phosphoric acid(H₃PO₄) and hydrofluoric acid (HF) or nitric acid (HNO₃) have beenconventionally known; however, these technologies rather resulted inlowering of the etch selectivity between a nitride film and an oxidefilm. Furthermore, technologies of using a composition for etchingincluding phosphoric acid and a silicic acid salt or silicic acid arealso known; however, there is a problem that silicic acid or a silicicacid salt causes generation of particles that may adversely affect asubstrate and is therefore rather unsuitable for semiconductormanufacturing processes.

FIG. 1 and FIG. 2 are process cross-sectional views illustrating adevice separation process for a flash memory device.

First, as illustrated in FIG. 1, tunnel oxide film (11), polysiliconfilm (12), buffer oxide film (13), and pad nitride film (14) aresequentially formed on substrate (10), and then polysilicon film (12),buffer oxide film (13), and pad nitride film (14) are selectively etchedto form trenches. Subsequently, spin-on-dielectric (SOD) oxide film (15)is formed until the trenches are gap-filled, and then SOD oxide film(15) is subjected to a chemical mechanical polishing (CMP) process byusing pad nitride film (14) as a polishing stopper film.

Next, as illustrated in FIG. 2, pad nitride film (14) is removed by wetetching using a phosphoric acid solution, and then buffer oxide film(13) is removed by a washing process. Thereby, device separation film(15A) is formed in the field region. However, in the case of usingphosphoric acid in such a wet etching process for removing a nitridefilm, due to a decrease in the etch selectivity between a nitride filmand an oxide film, a nitride film as well as an SOD oxide film areetched, and thus, it becomes difficult to regulate the effective fieldoxide height (EFH). Accordingly, a sufficient wet etching time forremoving a nitride film cannot be secured, or additional processes areneeded, and thus phosphoric acid causes changes and adversely affectsthe device characteristics.

Therefore, under the current circumstances, there is a demand for ahigh-selectivity composition for etching that can selectively etch anitride film with respect to an oxide film in a semiconductor productionprocess but does not have a problem such as particle generation.

DISCLOSURE Technical Problem

An object of the present invention is to provide a high-selectivitycomposition for etching that can selectively remove a nitride film whileminimizing the etch rate of an oxide film and does not have problemssuch as particle generation adversely affecting the devicecharacteristics, and a method of manufacturing a semiconductor deviceusing this composition for etching.

Technical Solution

A composition for etching according to an aspect of the presentinvention includes a first inorganic acid; any one first additiveselected from the group consisting of phosphorous acid, an organicphosphite, a hypophosphite, and mixtures thereof; and a solvent.

The first inorganic acid may be any one selected from the groupconsisting of sulfuric acid, nitric acid, phosphoric acid, silicic acid,fluoric acid, boric acid, hydrochloric acid, perchloric acid, andmixtures of these.

The organic phosphite may be any one alkyl phosphite selected from thegroup consisting of dimethyl phosphite, diethyl phosphite, dipropylphosphite, diisopropyl phosphite, dibutyl phosphite, trimethylphosphite, triethyl phosphite, tripropyl phosphite, triisopropylphosphite, tributyl phosphite, diphenyl phosphite, dibenzyl phosphite,and mixtures of these.

The hypophosphite may be any one selected from the group consisting ofammonium hypophosphite, sodium hypophosphite, potassium hypophosphite,and mixtures of these.

The composition for etching may include 0.01% to 15% by weight of thefirst additive, 70% to 99% by weight of the first inorganic acid, andthe solvent occupying the balance.

The composition for etching may further include a second additive thatincludes a silane inorganic acid salt produced by reacting a secondinorganic acid and a silane compound.

The silane inorganic acid salt may be a silane inorganic acid saltproduced by reacting any one second inorganic acid selected from thegroup consisting of sulfuric acid, fuming sulfuric acid, nitric acid,phosphoric acid, anhydrous phosphoric acid, and mixtures thereof, with asilane compound represented by the following Chemical Formula 10.

In Chemical Formula 10, R¹ to R⁴ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; and atleast any one of R¹ to R⁴ represents a halogen atom or an alkoxy grouphaving 1 to 10 carbon atoms.

The silane inorganic acid salt may be a silane inorganic acid saltproduced by reacting a second inorganic acid including polyphosphoricacid with a silane compound represented by the following ChemicalFormula 10.

In Chemical Formula 10, R¹ to R⁴ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; and atleast one of R¹ to R⁴ is a halogen atom or an alkoxy group having 1 to10 carbon atoms.

The silane inorganic acid salt may include a compound represented by thefollowing Chemical Formula 100.

In Chemical Formula 100, R¹ represents any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; n₁ represents an integer from 1to 4; m₁ represents an integer from 1 to 10; and R² to R⁴ each representa hydrogen atom.

The silane inorganic acid salt represented by Chemical Formula 100 issuch that any one of the hydrogen atoms represented by R² to R⁴ may besubstituted with a substituent represented by the following ChemicalFormula 120.

In Chemical Formula 120, any one of R⁵'s represents a linking grouplinked to a structure represented by Chemical Formula 100, while theothers each independently represent any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; R² to R⁴ each independentlyrepresent a hydrogen atom or a second substituent represented byChemical Formula 120; n₂ represents an integer from 0 to 3; and m₂represents an integer from 1 to 10.

The silane inorganic acid salt may be a siloxane inorganic acid saltproduced by reacting any one second inorganic acid selected from thegroup consisting of phosphoric acid, anhydrous phosphoric acid,pyrophosphoric acid, polyphosphoric acid, and a mixture thereof, with asiloxane compound represented by the following Chemical Formula 20.

In Chemical Formula 20, R⁵ to R¹⁰ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; at leastany one of R⁵ to R¹⁰ represents a halogen atom or an alkoxy group having1 to 10 carbon atoms; and n represents an integer from 1 to 10.

The siloxane inorganic acid salt may include a compound represented bythe following Chemical Formula 200.

In Chemical Formula 200, R¹ to R² each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; n₁represents an integer from 0 to 3; n₂ represents an integer from 0 to 2;m₁ represents an integer of 0 or 1; the relation: n₁+n₂+m₁≥1 issatisfied; 1₁ represents an integer from 1 to 10; o₁ to o₃ eachindependently represent an integer from 0 to 10; and R³ to R¹¹ eachindependently represent a hydrogen atom.

The siloxane inorganic acid salt represented by Chemical Formula 200 issuch that any one hydrogen atom selected from the group consisting of R³to R¹¹ may be substituted by a substituent represented by the followingChemical Formula 220.

In Chemical Formula 220, any one of R¹²'s and R¹³'s represents a linkinggroup linked to a structure represented by Chemical Formula 200, whilethe others each independently represent any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; R³ to R¹¹ each independentlyrepresent a hydrogen atom or a second substituent represented byChemical Formula 220; n₃ represents an integer from 0 to 3; n₄represents an integer from 0 to 2; m₁ represents an integer of 0 to 1;1₁ represents an integer from 1 to 10; and o₁ to o₃ each independentlyrepresent an integer from 0 to 10.

The silane inorganic acid salt may be a siloxane inorganic acid saltproduced by reacting any one second inorganic acid selected from thegroup consisting of sulfuric acid, fuming sulfuric acid, and a mixturethereof, with a siloxane compound represented by the following ChemicalFormula 20.

In Chemical Formula 20, R⁵ to R¹⁰ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; at leastany one of R⁵ to R¹⁰ represents a halogen atom or an alkoxy group having1 to 10 carbon atoms; and n represents an integer from 1 to 10.

The siloxane inorganic acid salt may include a compound represented bythe following Chemical Formula 230.

In Chemical Formula 230, R²¹ and R²² each independently represent anyone selected from the group consisting of a hydrogen atom, a halogenatom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having1 to 10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; n₁represents an integer from 0 to 3; n₂ represents an integer from 0 to 2;m₁ represents an integer of 0 or 1; the relation: n₁+n₂+m₁ is satisfied;1₁ represents an integer from 1 to 10; and R²³ to R²⁵ each represent ahydrogen atom.

The siloxane inorganic acid salt represented by Chemical Formula 230 issuch that any one hydrogen atom selected from the group consisting ofR²³ to R²⁵ may be substituted by a substituent represented by thefollowing Chemical Formula 250.

In Chemical Formula 250, any one of R²⁶'s and R²⁷'s represents a linkinggroup linked to a structure represented by Chemical Formula 230, whilethe others each independently represent any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; R²³ to R²⁵ each independentlyrepresent a hydrogen atom or a second substituent represented byChemical Formula 250; n₃ represents an integer from 0 to 3; n₄represents an integer from 0 to 2; m₁ represents an integer of 0 or 1;and 1₁ represents an integer from 1 to 10.

The silane inorganic acid salt may be a siloxane inorganic acid saltproduced by reacting a second inorganic acid including nitric acid, witha siloxane compound represented by the following Chemical Formula 20.

In Chemical Formula 20, R⁵ to R¹⁰ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; at leastany one of R⁵ to R¹⁰ represents a halogen atom or an alkoxy group having1 to 10 carbon atoms; and n represents an integer from 1 to 10.

The siloxane inorganic acid salt may include a compound represented bythe following Chemical Formula 260.

In Chemical Formula 260, R³¹ and R³² each independently represent anyone selected from the group consisting of a hydrogen atom, a halogenatom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having1 to 10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; n₁represents an integer from 0 to 3; n₂ represents an integer from 0 to 2;m₁ represents an integer of 0 or 1; the relation: n₁+n₂+m₁≥1 issatisfied; 1₁ represents an integer from 1 to 10; and R³³ to R³⁵ eachindependently represent a hydrogen atom.

The siloxane inorganic acid salt represented by Chemical Formula 260 issuch that any one hydrogen atom selected from the group consisting ofR³³ to R³⁵ may be substituted by a substituent represented by thefollowing Chemical Formula 280.

In Chemical Formula 280, any one of R³⁶'s and R³⁷'s represents a linkinggroup linked to a structure represented by Chemical Formula 260, whilethe others each independently represent any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; R³³ to R³⁵ each independentlyrepresent a hydrogen atom or a second substituent represented byChemical Formula 280; n₃ represents an integer from 0 to 3; n₄represents an integer from 0 to 2; m₁ represents an integer of 0 or 1;and 1₁ represents an integer from 1 to 10.

The composition for etching may further include a second additiveincluding an alkoxysilane compound represented by the following ChemicalFormula 300.

In Chemical Formula 300, R¹ to R⁴ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom, ahydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxygroup having 1 to 10 carbon atoms, an aminoalkyl group having 1 to 10carbon atoms, an aminoalkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; and at least any one of R¹ to R⁴represents an alkoxy group having 1 to 10 carbon atoms, an aminoalkylgroup having 1 to 10 carbon atoms, or an aminoalkoxy group having 1 to10 carbon atoms.

The composition for etching may further include a second additiveincluding a siloxane compound represented by the following ChemicalFormula 350.

In Chemical Formula 350, R² to R⁵ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom, ahydroxyl group, an alky group having 1 to 10 carbon atoms, an alkoxygroup having 1 to 10 carbon atoms, an aminoalkyl group having 1 to 10carbon atoms, an aminoalkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; at least any one of R² to R⁵represents an alkoxy group having 1 to 10 carbon atoms, an aminoalkylgroup having 1 to 10 carbon atoms, or an aminoalkoxy group having 1 to10 carbon atoms; and n represents an integer from 1 to 4.

The composition for etching may further include a second additiveincluding an oxime compound represented by the following ChemicalFormula 400.

In Chemical Formula 400, R¹ and R² each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, acycloalkyl group having 3 to 20 carbon atoms, an aminoalkyl group having1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, analkylcarbonyl group having 1 to 20 carbon atoms, an alkylcarbonyloxygroup having 1 to 20 carbon atoms, and a cyanoalkyl group having 1 to 10carbon atoms.

The oxime compound may be any one selected from the group consisting ofacetone oxime, 2-butanone oxime, acetaldehyde oxime, cyclohexanoneoxime, acetophenone oxime, cyclodecanone oxime, and mixtures thereof.

The composition for etching may further include a second additiveincluding an oxime silane compound represented by the following ChemicalFormula 500.

In Chemical Formula 500, R¹ to R³ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an arylgroup having 6 to 20 carbon atoms, an arylalkyl group having 7 to 20carbon atoms, and an alkylcarbonyl group having 1 to 20 carbon atoms; R⁴and R⁵ each independently represent an alkyl group having 1 to 20 carbonatoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl grouphaving 6 to 20 carbon atoms, an arylalkyl group having 7 to 20 carbonatoms, and an alkylcarbonyl group having 1 to 20 carbon atoms; or R⁴ andR⁵ each represent an alkylene group having 3 to 12 carbon atoms or arelinked to each other to form an alicyclic ring; x, y, and z eachindependently represent an integer from 0 to 3; and x+y+z represents aninteger from 0 to 3.

The oxime silane compound may be any one selected from the groupconsisting of di(ethyl ketoxime)silane, mono(ethyl ketoxime)silane,tris(ethyl ketoxime)silane, tetra(ethyl ketoxime)silane, methyltris(methyl ethyl ketoxime)silane, methyl tris(methyl ethylketoxime)silane, methyl tris(acetoxime)silane, methyl tris(methylisobutyl ketoxime)silane, dimethyl di(methyl ethyl ketoxime)silane,trimethyl (methl ethyl ketoxime)silane, tetra(methyl ethylketoxime)silane, tetra(methyl isobutyl ketoxime)silane, vinyltris(methyl ethyl ketoxime)silane, methyl vinyl di(methyl ethylketoxime)silane, vinyl tris(methyl isobutyl ketoxime)silane, and phenyltris(methyl ethyl ketoxime)silane.

The composition for etching may include the second additive in an amountof 0.01% to 20% by weight with respect to the total amount of thecomposition for etching.

The composition for etching may further include an ammonium-basedcompound in an amount of 0.01% to 20% by weight with respect to thetotal amount of the composition for etching.

The ammonium-based compound may be any one selected from the groupconsisting of an aqueous ammonia solution, ammonium chloride, ammoniumacetate, ammonium phosphate, ammonium peroxydisulfate, ammonium sulfate,ammonium borate, and mixtures thereof.

The composition for etching may further include a fluorine-basedcompound in an amount of 0.01% to 1% by weight with respect to the totalamount of the composition for etching.

The fluorine-based compound may be any one selected from the groupconsisting of hydrogen fluoride, ammonium fluoride, ammonium hydrogenfluoride, and mixtures thereof.

A method of manufacturing a semiconductor device according to anotherembodiment of the present invention includes an etching process carriedout using the composition for etching.

The etching process is intended for selective etching of a nitride filmwith respect to an oxide film, and the nitride film etching process maybe carried out at a temperature of 50° C. to 300° C.

Advantageous Effects

Since the composition for etching according to the invention has afeature that the etch selectivity for a nitride film with respect to anoxide film is high, the EFH can be easily regulated by regulating theetch rate for an oxide film.

Furthermore, when the composition for etching of the invention is used,damage to the film quality of an oxide film or deterioration ofelectrical characteristics caused by etching of an oxide film at thetime of removing a nitride film can be prevented, particle generationcan be prevented, and the device characteristics can be improved.

Therefore, the present invention is widely applicable to variousprocesses such as a semiconductor production process where selectiveremoval of a nitride film with respect to an oxide film is required; adevice separation process for, for example, a flash memory device; aprocess for forming a pipe channel in a 3D flash memory device; and aprocess for forming a diode in a phase change memory, and the presentinvention can improve the process efficiency.

DESCRIPTION OF DRAWINGS

FIG. 1 and FIG. 2 are process cross-sectional views illustrating adevice separation process for a flash memory device according toconventional technologies.

FIG. 3 to FIG. 5 are process cross-sectional views for explaining adevice separation process for a flash memory device, including anetching process of using a composition for etching according anembodiment of the invention.

FIG. 6 to FIG. 11 are process cross-sectional views for explaining apipe channel forming process for a flash memory device, including anetching process of using a composition for etching according to anembodiment of the invention.

FIG. 12 and FIG. 13 are process cross-sectional views for explaining adiode forming process for a phase change memory, including an etchingprocess of using a composition for etching according to anotherembodiment of the invention.

BEST MODE

The present invention may be subjected to various modifications and mayinclude various embodiments, and thus particular embodiments will bedescribed in detail in the detailed description of the invention.However, it is not intended to limit the invention by any particularembodiments, and it should be construed that the present inventionincludes all modifications, equivalents, and replacements that areincluded in the idea and technical scope of the invention.

The terms used in the invention are used only for the purpose ofexplaining particular embodiments and are not intended to limit theinvention by any means. The expression of singularity includes theexpression of plurality, unless stated otherwise in the context. Itshould be understood that the terms “include” or “have” as used in theinvention are intended to indicate the existence of the features,values, stages, actions, constituent elements, component parts, orcombinations thereof described in the specification, and the existenceor a possibility of addition of one or more other features, values,stages, actions, constituent elements, component parts, and combinationsthereof is not to be excluded in advance.

According to the present specification, an alkyl group having 1 to 10carbon atoms represents a linear or branched non-cyclic saturatedhydrocarbon having 1 to 10 carbon atoms, and an alkoxy group having 1 to10 carbon atoms represents a linear or branched non-cyclic hydrocarbonhaving one or more ether groups and 1 to 10 carbon atoms.

The composition for etching according to an embodiment of the inventionincludes a first inorganic acid; any one first additive selected fromthe group consisting of phosphorous acid, an organic phosphite, ahypophosphite, and mixtures thereof; and a solvent.

The any one first additive selected from the group consisting ofphosphorous acid, an organic phosphite, a hypophosphite, and mixturesthereof is preferable from the viewpoint of having excellent solubilityin the first inorganic acid and from the viewpoint that stability of thefirst inorganic acid at high temperature can be secured. Furthermore,the process use time of the composition for etching can be prolonged byusing the first additive.

The organic phosphite may be specifically an alkyl phosphite, and thealkyl phosphite may be any one selected from the group consisting ofdimethyl phosphite, diethyl phosphite, dipropyl phosphite, diisopropylphosphite, dibutyl phosphite, trimethyl phosphite, triethyl phosphite,tripropyl phosphite, triisopropyl phosphite, tributyl phosphite,dibenzyl phosphite, and mixtures thereof. Among these, it is preferableto use dimethyl phosphite, from the viewpoint that high solubility inthe first inorganic acid and process stability can be secured.

The hypophosphite may be any one selected from the group consisting ofammonium hypophosphite, sodium hypophosphite, potassium hypophosphite,and mixtures thereof, and the hypophosphite is preferably ammoniumhypophosphite. The ammonium hypophosphite is a non-metal additive and ishelpful in securing the stability of the semiconductor productionprocess.

The content of the first additive may be 0.01% to 15% by weight,preferably 0.5% to 15% by weight, more preferably 1% to 15% by weight,and even more preferably 3% to 7% by weight, with respect to the totalweight of the composition for etching. When the content of the firstadditive is less than 0.01% by weight, high etch selectivity withrespect to a nitride film cannot be obtained, and when the content ismore than 15% by weight, it is difficult to expect a further increase ineffect associated with an increase in the content, and thermaldecomposition of the additive may rather reduce the effect.

Meanwhile, the composition for etching may further include a secondadditive such as described below, in addition to the first additive.

The second additive may include a silane inorganic acid salt produced byreacting a second inorganic acid with a silane compound. The silaneinorganic acid salt can facilitate regulation of an effective fieldoxide height (EFH) by regulating the etching rate for an oxide film.

According to an embodiment, the silane inorganic acid salt can beproduced by reacting the second inorganic acid with the silane compound.Since the silane inorganic acid salt is produced by reacting the secondinorganic acid with the silane compound, the silane inorganic acid saltmay be not a compound having a single chemical structure, but a mixtureof silane inorganic acid salts having various chemical structures. Thatis, the second additive may include a mixture of at least two or moresilane inorganic acid salts having different chemical structures.However, the invention is not intended to be limited to this, and thesecond additive may include only one kind of silane inorganic acid salt.

The second inorganic acid may be any one selected from the groupconsisting of sulfuric acid, fuming sulfuric acid, nitric acid,phosphoric acid, anhydrous phosphoric acid, pyrophosphoric acid,polyphosphoric acid, and mixtures thereof, and the second inorganic acidis preferably sulfuric acid, nitric acid, or phosphoric acid.

The silane compound may be any one selected from the group consisting ofa compound represented by the following Chemical Formula 10, a compoundrepresented by the following Chemical Formula 20, and a mixture thereof.

In Chemical Formula 10, R¹ to R⁴ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; and atleast any one of R¹ to R⁴ is a halogen atom or an alkoxy group having 1to 10 carbon atoms.

The halogen atom may be a fluoro group, a chloro group, a bromo group,or an iodo group, and preferably a fluoro group or a chloro group.

Specifically, the compound represented by Chemical Formula 10 may be ahalosilane or alkoxysilane compound.

The halosilane compound may be any one selected from the groupconsisting of trimethylchlorosilane, triethylchlorosilane,tripropylchlorosilane, trimethylfluorosilane, triethylfluorosilane,tripropylfluorosilane, dimethyldichlorosilane, diethyldichlorosilane,dipropyldichlorosilane, dimethyldifluorosilane, diethyldifluorosilane,dipropyldifluorosilane, ethyltrichlorosilane, propyltrichlorosilane,methyltrifluorosilane, ethyltrifluorosilane, propyltrifluorosilane, andmixtures thereof.

The alkoxysilane compound may be any one selected from the groupconsisting of tetramethoxysilane (TMOS), tetrapropoxysilane,methyltrimethoxysilane (MTMOS), methyltriethoxysilane (MTEOS),methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,ethyltripropoxysilane, propyltrimethoxysilane (PrTMOS),propyltriethoxysilane (PrTEOS), propyltripropoxysilane,dimethyldimethoxysilane, dimethyldiethoxysilane,dimethyldipropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane,diethyldipropoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane,dipropyldipropoxysilane, trimethylmethoxysilane, trimethylethoxysilane,trimethylpropoxysilane, triethylmethoxysilane, triethylethoxysilane,triethylpropoxysilane, tripropylmethoxysilane, tripropylethoxysilane,tripropylpropoxysilane, 3-chloropropyltrimethoxysilane,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,[3-(2-aminoethyl)aminopropyl]trimethoxysilane,3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane,3-acryloxypropyltrimethoxysilane, and mixtures thereof.

In Chemical Formula 20, R⁵ to R¹⁰ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; at leastany one of R⁵ to R¹⁰ represents a halogen atom or an alkoxy group having1 to 10 carbon atoms; and n represents an integer from 1 to 10.

The halogen atom may be a fluoro group, a chloro group, a bromo group,or an iodo group, and the halogen atom is preferably a fluoro group or achloro group.

Specifically, examples of the compound represented by Chemical Formula20 include chlorodimethylsiloxy-chlorodimethylsilane,chlorodiethylsiloxy-chlorodimethylsilane,dichloromethylsiloxy-chlorodimethylsilane,dichloroethylsiloxy-chlorodimethylsilane,trichlorosiloxy-chlorodimethylsilane,fluorodimethylsiloxy-chlorodimethylsilane,difluoromethylsiloxy-chlorodimethylsilane,trifluorosiloxy-chlorodimethylsilane,methoxydimethylsiloxy-chlorodimethylsilane,dimethoxymethylsiloxy-chlorodimethylsilane,trimethoxysiloxy-chlorodimethylsilane,ethoxydimethylsiloxy-chlorodimethylsilane,diethoxymethylsiloxy-chlorodimethylsilane,triethoxysiloxy-chlorodimethylsilane,chlorodimethylsiloxy-dichloromethylsilane,trichlorosiloxy-dichlroomethylsilane,chlorodimethylsiloxy-trichlorosilane,dichloromethylsiloxy-trichlorosilane, andtrichlorosiloxy-trichlorosilane.

The silane inorganic acid salt can be produced by adding the silanecompound to the second inorganic acid, and then causing the mixture toreact at a temperature of 20° C. to 300° C., and preferably 50° C. to200° C. At this time, the reaction may be carried out while air andmoisture are removed. When the reaction temperature is below 20° C., thesilane compound may be crystallized, or the silane compound may bevaporized due to a low reaction rate. When the reaction temperature isabove 300° C., the second inorganic acid may evaporate.

The second inorganic acid and the silane compound can be reacted at aproportion of 0.001 to 50 parts by weight, and preferably 0.01 to 30parts by weight, of the silane compound with respect to 100 parts byweight of the second inorganic acid. When the amount of the silanecompound reacted is less than 0.001 parts by weight, realization of theselectivity may be difficult due to the small content ratio of thesilane compound, and when the amount is more than 50 parts by weight,the silane compound may be precipitated, or an amorphous structure maybe produced.

Volatile side products that are generated at the time of reaction can beremoved by distillation under reduced pressure. The product of theabove-described reaction may be purified to separate the silaneinorganic acid salt, and then this salt may be added to the compositionfor etching. Alternatively, it is also possible to add the reactionproduct to the composition for etching without purification.

The reaction can be carried out in the presence or absence of an aproticsolvent, and in the case of using an aprotic solvent, a solvent orsolvent mixture having a boiling point or a boiling range up to 120° C.at 10,013 mbar can be preferably used. Examples of the solvent includedioxane, tetrahydrofuran, diethyl ether, diisopropyl ether, diethyleneglycol dimethyl ether; chlorinated hydrocarbons, for example,dichloromethane, trichloromethane, tetrachloromethane,1,2-dichloroethane, and trichloroethylene; hydrocarbons, for example,pentane, n-hexane, a mixture of hexane isomers, heptanes, octane,benzine, petroleum ether, benzene, toluene, and xylene; ketones, forexample, acetone, methyl ethyl ketone, diisopropyl ketone, and methylisobutyl ketone (MIBK); esters, for example, ethyl acetate, butylacetate, propyl propionate, ethyl butyrate, ethyl isobutyrate, carbondisulfide, and nitrobenzene; and mixtures of these solvents.

As described above, since the silane inorganic acid salt is produced byreacting the second inorganic acid with the silane compound, the silaneinorganic acid salt may be not a compound having a single chemicalstructure, but a mixture of silane inorganic acid salts having variouschemical structures. That is, the silane inorganic acid salts may be aproduct resulting from alternate reactions between the second inorganicacid and the silane compound, or may be a mixture of silane inorganicacid salts having various chemical structures obtained as a result ofreacting into a linear form or a branched form depending on the numberand positions of halogen atoms in the silane compound.

Specific examples of the silane inorganic acid salts having variouschemical structures include compounds of the following chemicalformulas. However, the silane inorganic acid salt of the invention isnot limited to the following chemical structures.

In Chemical Formulas 51 to 57, 61 to 67, and 71 to 77, R¹⁻¹ to R¹⁻⁸ eachindependently represent any one selected from the group consisting of ahydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbonatoms, an alkoxy group having 1 to 10 carbon atoms, and an aryl grouphaving 6 to 30 carbon atoms; and the halogen atom may be a fluoro group,a chloro group, a bromo group, or an iodo group, while the halogen atomis preferably a fluoro group or a chloro group.

The content of the silane inorganic acid salt is 0.01% to 15% by weight,preferably 0.5% to 15% by weight, more preferably 1% to 15% by weight,and more preferably 3% to 7% by weight, with respect to the total weightof the composition for etching. When the content of the silane inorganicacid salt is less than 0.01% by weight, a high etch selectivity for anitride film cannot be obtained, and when the content is more than 15%by weight, it is difficult to expect a further increase in effectassociated with an increase in the content, and there may rather beproblems such as particle generation.

At this time, when the content of the silane inorganic acid salt is 0.7%by weight or more, the selectivity between the nitride etch rate (Å/min)and the oxide etch rate (Å/min) of the composition for etching may be200:1 or greater (nitride etch rate:oxide etch rate), for example,200:1, 200:5, or 200:10. When the content of the silane inorganic acidsalt is 1.4% by weight or more, the selectivity between the nitride etchrate (Å/min) and the oxide etch rate (Å/min) of the composition foretching may be 200:infinity (nitride etch rate:oxide etch rate). Sincethe composition for etching has a feature of having high etchselectivity for a nitride film with respect to an oxide film asdescribed above, the EFH can be easily regulated by regulating the etchrate for an oxide film.

According to another embodiment, the silane inorganic acid salt can beproduced by reacting polyphosphoric acid with the silane compoundrepresented by Chemical Formula 10. At this time, the silane inorganicacid salt can be represented by the following Chemical Formula 100.

In Chemical Formula 100, R¹ represents any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; and the halogen atom may be afluoro group, a chloro group, a bromo group, or an iodo group, while thehalogen atom is preferably a fluoro group or a chloro group.

n₁ represents an integer from 1 to 4, and m₁ represents an integer from1 to 10.

R² to R⁴ each represent a hydrogen atom. However, optionally, any onehydrogen atom selected from the group consisting of R² to R⁴ may besubstituted by a substituent represented by the following ChemicalFormula 120.

In Chemical Formula 120, any one of R⁵'s represents a linking grouplinked to a structure represented by Chemical Formula 100, and theothers each independently represent any one selected from a hydrogenatom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, analkoxy group having 1 to 10 carbon atoms, and an aryl group having 6 to30 carbon atoms. That is, in a case in which there are four units of R⁵,one of them is a linking group linked to a structure of Chemical Formula100, and the other three may be each independently any one selected fromthe group consisting of a hydrogen atom, a halogen atom, an alkyl grouphaving 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbonatoms, and an aryl group having 6 to 30 carbon atoms. Furthermore, in acase in which there is only one unit of R⁵, this R⁵ represents a linkinggroup linked to a structure of Chemical Formula 100.

n₂ represents an integer from 0 to 3, and m₂ represents an integer from1 to 10.

In Chemical Formula 120, R² to R⁴ may be each a hydrogen atom, or may besubstituted by a second substituent represented by Chemical Formula 120.That is, a second substituent represented by Chemical Formula 120 may besubstituted at any one of the R²-position to the R⁴-position, and athird substituent represented by Chemical Formula 120 may be substitutedat any one of the R²-position to R⁴-position of the second substituentrepresented by Chemical Formula 120.

This is because the silane inorganic acid salt is a product produced byreacting the polyphopshoric acid with the silane compound. That is, thecompound represented by Chemical Formula 100 is produced as a result ofthe reaction between the polyphosphoric acid and the silane compound,and a hydroxyl group at any one of the R²-position to the R⁴-position ofa moiety derived from the polyphosphoric acid may react again with thesilane compound, which is a reaction starting substance. Subsequently,the silane compound that has reacted with the compound represented byChemical Formula 100 may react again with the polyphosphoric acid, whichis a reaction starting substance, and such a reaction may proceedcontinuously.

An example of the silane inorganic acid salt resulting from the resultsof continuous proceeding of the reaction is as follows.

An example of the case in which in Chemical Formula 100, n₁ represents1; m₁ represents 1; and R² to R⁴ all represent a hydrogen atom may beequivalent to the following Chemical Formula 101. At this time, thedefinitions for R¹⁻¹ to R¹⁻³ are the same as the definitions for R¹.

A compound represented by the following Chemical Formula 102 is the sameas the compound represented by Chemical Formula 101, except that m₁ is2.

An example of the case in which in Chemical Formula 100, n₁ represents2; m₁ represents 1; and R² to R⁴ all represent a hydrogen atom may beequivalent to the following Chemical Formula 103. At this time, thedefinitions for R¹⁻¹ and R¹⁻² are the same as the definitions for R¹.

An example of the case in which in Chemical Formula 100, n₁ represents1; m₁ represents 1; R² and R³ both represent a hydrogen atom; and R⁴ issubstituted by a substituent represented by Chemical Formula 120, may beequivalent to the following Chemical Formula 104. In Chemical Formula120, n₂ represents zero, and any one of R⁵'s represents a linking grouplinked to a structure represented by Chemical Formula 100. At this time,the definitions for R¹⁻¹ to R¹⁻⁶ are the same as the definitions for R¹.A compound represented by the following Chemical Formula 104 is aresultant product produced when the moiety derived from thepolyphosphoric acid and having a substituent represented by R⁴ in thecompound represented by Chemical Formula 100 reacts again with thesilane compound as a reaction starting substance.

An example of the case in which in Chemical Formula 100, n₁ represents1; m₁ represents 1; R³ and R⁴ each represent a hydrogen atom; and R² issubstituted with a substituent represented by Chemical Formula 120, maybe equivalent to the following Chemical Formula 105. In Chemical Formula120, n₂ represents 1; m₂ represents 1; any one of R⁵'s represents alinking group linked to a structure represented by Chemical Formula 100;and R² to R⁴ all represent a hydrogen atom. At this time, thedefinitions for R¹⁻¹ to R¹⁻⁵ are the same as the definitions for R¹described above. A compound represented by the following ChemicalFormula 105 is a resultant product produced when a hydroxyl group at anyone of the R⁴-position of a moiety derived from the polyphosphoric acidin the compound represented by Chemical Formula 100 reacts again withthe silane compound as a reaction starting substance, and subsequentlythe silane compound that has reacted with the compound represented byChemical Formula 100 reacts again with the polyphosphoric acid as areaction starting substance.

Compounds represented by the following Chemical Formula 106 and ChemicalFormula 107 are the same as the compound represented by Chemical Formula105, except that the position of the substituent represented by ChemicalFormula 120 has been changed from the R²-position of Chemical Formula100 to the R³-position and the R⁴-position, respectively.

An example of the case in which in Chemical Formula 100, n₁ represents1; m₁ represents 1; R² and R³ each represent a hydrogen atom; R⁴ issubstituted by a substituent represented by Chemical Formula 120; and asecond substituent represented by Chemical Formula 120 is substituted atthe R⁴-position of the substituent represented by Chemical Formula 120,may be equivalent to the following Chemical Formula 108. In ChemicalFormula 120, n₂ represents 1, m₂ represents 1; any one of R⁵'srepresents a linking group linked to a structure represented by ChemicalFormula 100; and R² and R³ are hydrogen atoms. At this time, thedefinitions for R¹⁻¹ to R¹⁻⁷ are the same as the definition for R¹described above. A compound represented by the following ChemicalFormula 108 is a resultant product produced when a hydroxyl group of amoiety derived from the polyphosphoric acid on the right-hand sideterminal of the compound represented by Chemical Formula 107 reactsagain with the silane compound as a reaction starting substance, andsubsequently the silane compound that has reacted with the compoundrepresented by Chemical Formula 107 reacts again with the polyphosphoricacid as a reaction starting substance.

The present invention is not intended to be limited to the compoundsexemplified by Chemical Formulas 101 to 108, and various modificationscan be made based on the compounds described above as references.

Meanwhile, the silane compound that can react with the polyphosphoricacid and thereby produce the silane inorganic acid salt represented byChemical Formula 100 may be a compound represented by Chemical Formula10 described above. The details of the compound represented by ChemicalFormula 10 are as described above.

The polyphosphoric acid may be pyrophosphoric acid containing twophosphorus atoms, or a polyphosphoric acid containing three or morephosphorus atoms.

The method of manufacturing the silane inorganic acid salt by reactingthe polyphosphoric acid with the silane compound is the same as themethod of manufacturing the silane inorganic acid salt by reacting thesecond inorganic acid with the silane compound, except that thepolyphosphoric acid is used instead of the second inorganic acid.

According to an embodiment, the silane inorganic acid salt may be asiloxane inorganic acid salt produced by reacting any one secondinorganic acid selected from the group consisting of phosphoric acid,phosphoric acid anhydride, pyrophosphoric acid, polyphosphoric acid, andmixtures thereof, with a siloxane compound represented Chemical Formula20.

At this time, the siloxane inorganic acid salt may be represented by thefollowing Chemical Formula 200.

In Chemical Formula 200, R¹ and R² each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; and thehalogen atom may be a fluoro group, a chloro group, a bromo group, or aniodo group, while the halogen atom is preferably a fluoro group or achloro group.

n₁ represents an integer from 0 to 3; n₂ represents an integer from 0 to2; m₁ represents an integer of 0 or 1; and the relation: n₁+n₂+m₁≥1 issatisfied. That is, Chemical Formula 200 includes at least one atomicgroup derived from the second inorganic acid such as phosphoric acid.

1₁ represents an integer from 1 to 10; and o₁ to o₃ each independentlyrepresent an integer from 0 to 10.

R³ to R¹¹ each represent a hydrogen atom. However, any one hydrogen atomselected from the group consisting of R³ to R¹¹ may be selectivelysubstituted by a substituent represented by the following ChemicalFormula 220.

In Chemical Formula 220, any one of R¹²'s and R¹³'s represents a linkinggroup linked to a structure represented by Chemical Formula 200, and theothers each independently represent any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms. That is, in a case in whichthere are two units of R¹² and one unit of R¹³, one of them mayrepresent a linking group linked to a structure represented by ChemicalFormula 200, and the other two may each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms.Furthermore, in a case in which there is one unit of R¹² and zero unitsof R¹³, R¹² is a linking group linked to a structure represented byChemical Formula 200.

n₃ represents an integer from 0 to 3; n₄ represents an integer from 0 to2; and m₁ represents an integer of 0 or 1. 1₁ represents an integer from1 to 10, and o₁ to o₃ each independently represent an integer from 0 to10.

R³ to R¹¹ may each independently represent a hydrogen atom or may beeach independently substituted by a second substituent represented byChemical Formula 220. That is, a second substituent represented byChemical Formula 220 may be substituted at any one of the R³-position tothe R¹¹-position, and a third substituent represented by ChemicalFormula 220 may also be substituted at any one of the R³-position to theR¹¹-position of the second substituent represented by Chemical Formula220.

This is because the siloxane inorganic acid salt is a product producedby reacting the second inorganic acid with the siloxane compound. Thatis, the second inorganic acid reacts with the siloxane compound, and acompound represented by Chemical Formula 200 described above isproduced. A hydroxyl group at any one of the R³-position to theR¹¹-position of a moiety derived from the second inorganic acid in thecompound represented by Chemical Formula 200 can react again with thesiloxane compound as a reaction starting substance, and subsequently,the siloxane compound that has reacted with the compound represented byChemical Formula 200 can react again with the second inorganic acid as areaction starting substance. Thus, these reactions can proceedcontinuously.

Resultant products of the siloxane inorganic acid salts according to theresults of the successive progress of reactions are as follows.

An example of the case in which in Chemical Formula 200, n₁ represents1; n₂ represents zero; m1 represents zero; 1₁ represents 1; o₁ to o₃each represent zero; and R³ to R¹¹ all represent a hydrogen atom, may beequivalent to the following Chemical Formula 201. At this time, thedefinitions for R¹⁻¹ and R¹⁻² are the same as the definition for R¹described above, and the definitions for R²⁻¹ and R²⁻² are the same asthe definition for R² described above.

A compound represented by the following Chemical Formula 202 may be thesame as the compound represented by Chemical Formula 201, except that n₂is 1.

A compound represented by the following Chemical Formula 203 may be thesame as the compound represented by Chemical Formula 201, except that o₂and o₃ are both 1.

A compound represented by the following Chemical Formula 204 may be thesame as the compound represented by Chemical Formula 202, except that 1₁is 2.

An example of the case in which in Chemical Formula 200, n₁ and n₂ eachrepresent 2; m₁ represents zero; 11 represents 1; o₁ to o₃ eachrepresent zero; and R³ to R¹¹ all represent a hydrogen atom, may beequivalent to the following Chemical Formula 205.

An example of the case in which in Chemical Formula 200, n₁ represents1; n₂ represents 1; m₁ represents zero; 1₁ represents 1; o₁ to o₃ eachrepresent zero; R⁶, R⁹, and R¹¹ each represent a hydrogen atom; and R⁸is substituted by a substituent represented by Chemical Formula 220, maybe equivalent to the following Chemical Formula 206. In Chemical Formula220, n₃ and n₄ each represent zero; m₁ represents zero; 1₁ represents 1;any one of R¹²'s represents a linking group linked to a structurerepresented by Chemical Formula 200. At this time, the definitions forR¹⁻¹ to R¹⁻⁷ are the same as the definition for R¹, and the definitionfor R²⁻¹ is the same as the definition for R². A compound represented bythe following Chemical Formula 206 is a resultant product produced whena hydroxyl group at the R⁸-position of a moiety derived from the secondinorganic acid in the compound represented by Chemical Formula 200reacts again with the siloxane compound as a reaction startingsubstance.

An example of the case in which in Chemical Formula 200, n₁ represents1; n₂ represents 1; m₁ represents zero; 1₁ represents 1; o₁ to o₃ eachrepresent zero; R⁶, R⁹, and R¹¹ each represent a hydrogen atom; and R⁸is substituted by a substituent represented by Chemical Formula 220, maybe equivalent to the following Chemical Formula 207. In Chemical Formula220, n₃ and n₄ each represent 1; m₁ represents zero; o₂ and o₃ eachrepresent zero; any one of R¹²'s represents a linking group linked to astructure represented by Chemical Formula 200; and R⁶, R⁸, R⁹, and R¹¹each represent a hydrogen atom. At this time, the definitions for R¹⁻¹to R¹⁻³ are the same as the definition for R¹; the definitions for R²⁻¹and R²⁻² are the same as the definition for R²; and the definitions forR³⁻¹ and R³⁻² are the same as the definition for R³. A compoundrepresented by the following Chemical Formula 207 is a resultant productproduced when a hydroxyl group at the R⁸-position of a moiety derivedfrom the second inorganic acid in the compound represented by ChemicalFormula 200 reacts again with the siloxane compound as a reactionstarting substance, and subsequently the siloxane compound that hasreacted with the compound represented by Chemical Formula 200 reactsagain with the second inorganic acid as a reaction starting substance.

A compound represented by the following Chemical Formula 208 may be thesame as the compound represented by Chemical Formula 207, except thatthe substituent represented by Chemical Formula 220 is linked toChemical Formula 200 at the R¹⁻³-position of Chemical Formula 207.

An example of the case in which in Chemical Formula 200, n₁ represents1; n₂ represents 1; m₁ represents 0; 1₁ represents 1; o₁ to o₃ eachrepresent zero; R³, R⁶, R⁹, and R¹¹ each represent a hydrogen atom; R⁸is substituted by a first substituent represented by Chemical Formula220; and R⁸ of the first substituent represented by Chemical Formula 220is substituted by a second substituent represented by Chemical Formula220, may be equivalent to the following Chemical Formula 209. In thefirst substituent represented by Chemical Formula 220, n₃ and n₄ eachrepresent 1; m₁ represents zero; 1₁ represents 1; o₂ and o₃ eachrepresent zero; any one of R¹²'s represents a linking group linked to astructure represented by Chemical Formula 200; R⁶, R⁹, and R¹¹ eachrepresent a hydrogen atom; and R⁸ represents a second substituentrepresented by Chemical Formula 220. In the second substituentrepresented by Chemical Formula 220, n₃ and n₄ each represent 1; m₁represents 0; 1₁ represents 1; o₂ and o₃ each represent zero; any one ofR¹²'s represents a linking group linked to the first substituentrepresented by Genera Formula 220; and R⁶, R⁸, R⁹, and R¹¹ eachrepresent a hydrogen atom. At this time, the definitions for R¹⁻¹ toR¹⁻⁴ are the same as the definition for R¹; the definitions for R²⁻¹ toR²⁻³ are the same as the definition for R²; and the definitions for R³⁻¹to R³⁻³ are the same as the definition for R³.

A compound represented by the following Chemical Formula 209 is aresultant product produced when a moiety derived from the secondinorganic acid at the right-hand side end of the compound represented byChemical Formula 207, is reacted again with the siloxane compound as areaction starting substance, and subsequently the siloxane compound thathas reacted with the compound represented by Chemical Formula 207 reactsagain with the second inorganic acid as a reaction starting substance.

A compound represented by the following Chemical Formula 210 may be thesame as the compound represented by Chemical Formula 209, except thatthe second substituent represented by Chemical Formula 220 is linked toa structure represented by Chemical Formula 200 at the R¹⁻⁴-position ofChemical Formula 209.

The present invention is not intended to be limited to the compoundsrepresented by Chemical Formulas 201 to 210, and various modificationscan be made based on the compounds described above.

According to an embodiment, the silane inorganic acid salt may be asiloxane inorganic acid salt produced by reacting any one secondinorganic acid selected from the group consisting of sulfuric acid,fuming sulfuric acid, and a mixture thereof, with the siloxane compoundrepresented by Chemical Formula 20.

At this time, the siloxane inorganic acid salt may be represented by thefollowing Chemical Formula 230.

In Chemical Formula 230, R²¹ and R²² each independently represent anyone selected from the group consisting of a hydrogen atom, a halogenatom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having1 to 10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; andthe halogen atom may be a fluoro group, a chloro group, a bromo group,or an iodo group, while the halogen atom is preferably a fluoro group ora chloro group.

n₁ represents an integer from 0 to 3; n₂ represents an integer from 0 to2; m₁ represents an integer of 0 or 1; and the relation: n₁+n₂+m₁≥1 issatisfied. That is, Chemical Formula 230 contains at least one atomicgroup derived from the second inorganic acid such as sulfuric acid.

1₁ represents an integer from 1 to 10.

R²³ to R²⁵ each represent a hydrogen atom. However, any one hydrogenselected from the group consisting of R²³ to R²⁵ may be selectivelysubstituted by a substituent represented by the following ChemicalFormula 250.

In Chemical Formula 250, any one of R²⁶'s and R²⁷'s represents a linkinggroup linked to a structure represented by Chemical Formula 230; and theothers each independently represent any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms. That is, in a case in whichthere are two units of R²⁶ and one unit of R²⁷, one of them mayrepresent a linking group linked to a structure represented by ChemicalFormula 230, and the other two may each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms.Furthermore, in a case in which there are one unit of R²⁶ and zero unitsof R²⁷, R²⁶ is a linking group linked to a structure represented byChemical Formula 230.

n₃ represents an integer from 0 to 3; n₄ represents an integer from 0 to2; m₁ represents an integer of 0 or 1; and 1₁ represents an integer from1 to 10.

R²³ to R²⁵ may each independently represent a hydrogen atom, or may besubstituted by a second substituent represented by Chemical Formula 250.That is, a second substituent represented by Chemical Formula 250 may besubstituted at any one of the R²³-position to R²⁵-position, and a thirdsubstituent represented by Chemical Formula 250 may be substituted againat any one of the R²³-position to R²⁵-position.

When examples of the resultant products of the siloxane inorganic acidsalt obtained by the successive progress of reactions as described aboveare listed similarly to the cases of Chemical Formulas 201 to 210, theexamples include compounds represented by the following ChemicalFormulas 231 to 239. At this time, in the following Chemical Formulas231 to 239, the definitions for R¹¹⁻¹ to R¹¹⁻⁷ are the same as thedefinition for R¹¹; the definitions for R¹²⁻¹ to R¹²⁻³ are the same asthe definition for R¹²; and the definitions for R¹³⁻¹ to R¹³⁻³ are thesame as the definition for R¹³.

The present invention is not limited to the compounds listed above asexamples of Chemical Formulas 231 to 239, and various modifications canbe made based on the above-described compounds as references.

According to another embodiment, the silane inorganic acid salt may be asiloxane inorganic acid salt produced by reacting a second inorganicacid including nitric acid with the siloxane compound represented byChemical Formula 20.

At this time, the siloxane inorganic acid salt may be represented by thefollowing Chemical Formula 260.

In Chemical Formula 260, R³¹ and R³² each independently represent anyone selected from the group consisting of a hydrogen atom, a halogenatom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having1 to 10 carbon atoms, and an aryl group having 6 to 30 carbon atoms; andthe halogen atom may be a fluoro group, a chloro group, a bromo group,or an iodo group, while the halogen atom is preferably a fluoro group ora chloro group.

n₁ represents an integer from 0 to 3; n₂ represents an integer from 0 to2; m₁ represents an integer of 0 or 1; and the relation: n₁+n₂+m₁≥1 issatisfied. That is, Chemical Formula 260 contains at least one atomicgroup derived from the second inorganic acid including nitric acid.

1₁ represents an integer from 1 to 10.

R³³ to R³⁵ each independently represent a hydrogen atom. However, anyone hydrogen selected from the group consisting of R³³ to R³⁵ may beselectively substituted by a substituent represented by the followingChemical Formula 280.

In Chemical Formula 280, any one of R³⁶'s and R³⁷'s represents a linkinggroup linked to a structure represented by Chemical Formula 260, and theothers each independently represent any one selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group having 1to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms. That is, in a case in whichthere are two units of R³⁶ and one unit of R³⁷, one of them mayrepresent a linking group linked to a structure represented by ChemicalFormula 260, and the other two may each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to10 carbon atoms, and an aryl group having 6 to 30 carbon atoms.Furthermore, in a case in which there is one unit of R³⁶ and zero unitsof R³⁷, R³⁶ represents a linking group linked to a structure representedby Chemical Formula 260.

n₃ represents an integer from 0 to 3; n₄ represents an integer from 0 to2; m₁ represents an integer of 0 or 1; and 1₁ represents an integer from1 to 10.

R³³ to R³⁵ may each independently represent a hydrogen atom, or may beeach substituted by a second substituent represented by Chemical Formula280. That is, the second substituent represented by Chemical Formula 280may be substituted at any one of the R³³-position to the R³⁵-position,and a third substituent represented by Chemical Formula 280 may besubstituted again at any one of the R³³-position to the R³⁵-position ofthe second substituent represented by Chemical Formula 280.

When examples of the resultant products of the siloxane inorganic acidsalt obtained by the successive progress of reactions as described aboveare listed similarly to the cases of Chemical Formulas 201 to 210, theexamples include compounds represented by the following ChemicalFormulas 261 to 269. At this time, in the following Chemical Formulas261 to 269, the definitions for R²¹⁻¹ to R²¹⁻⁷ are the same as thedefinition for R²¹; the definitions for R²²⁻¹ to R²²⁻³ are the same asthe definition for R²²; and the definitions for R²³⁻¹ to R²³⁻³ are thesame as the definition for R²³.

The present invention is not intended to be limited to the compoundslisted as examples of Chemical Formulas 261 to 269, and variousmodifications can be made based on the above-described compounds asreferences.

Meanwhile, the siloxane compound that can react with the secondinorganic acid and produce the siloxane inorganic acid salt representedby Chemical Formula 200 may be a compound represented by the followingChemical Formula 20. The details of the compound represented by ChemicalFormula 20 are as described above.

The method of manufacturing the siloxane inorganic acid salt by reactingthe second inorganic acid with a siloxane compound is the same as themethod of manufacturing the silane inorganic acid salt by reacting thesecond inorganic acid with a silane compound, except that a siloxanecompound is used instead of a silane compound.

Furthermore, the second additive may include an alkoxysilane compoundrepresented by the following Chemical Formula 300.

In Chemical Formula 300, R¹ to R⁴ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom, ahydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxygroup having 1 to 10 carbon atoms, an aminoalkyl group having 1 to 10carbon atoms, an aminoalkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; and any one of R¹ to R⁴represents an alkoxy group having 1 to 10 carbon atoms, an aminoalkylgroup having 1 to 10 carbon atoms, or an aminoalkoxy group having 1 to10 carbon atoms.

Specifically, the alkoxysilane compound represented by Chemical Formula300 may be any one selected from the group consisting oftetramethoxysilane (TMOS), tetrapropoxysilane, methyltrimethoxysilane(MTMOS), methyltriethoxysilane (MTEOS), methyltripropoxysilane,ethyltrimethoxysilane, ethyltriethoxysilane, ethylthripropoxysilane,propyltrimethoxysilane (PrTMOS), propyltriethoxysilane (PrTEOS),propyltripropoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane,dimethyldipropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane,diethyldipropoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane,dipropyldipropoxysilane, trimethylmethoxysilane, trimethylethoxysilane,trimethylpropoxysilane, triethylmethoxysilane, triethylethoxysilane,triethylpropoxysilane, tripropylmethoxysilane, tripropylethoxysilane,tripropylpropoxysilane, 3-chloropropyltrimethoxysilane,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,[3-(2-aminoethyl)aminopropyl]trimethoxysilane,3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane,3-acryloxypropyltrimethoxysilane, and mixtures thereof. Furthermore, thealkoxysilane compound represented by Chemical Formula 300 may be any oneselected from the group consisting of butyl(methoxy)dimethylsilane,3-cyanopropyldimethylmethoxysilane, trimethylethoxysilane,trimethylmethoxysilane, hexyldimethoxysilane, methyldiethoxysilane,4-aminobutyldimethylmethoxysilane, 3-aminopropyldimethylethoxysilane,butyltrimethoxysilane, ethyltriethoxysilane, isobutyltriethoxysilane,methyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane,triethoxysilane, butyltriethoxysilane, trimethylpentylsilane,3-(2-aminoethyl)aminopropyltrimethoxysilane,3-aminopropyltriethoxysilane, tris(dimethylamino)silane, and mixturesthereof.

Furthermore, the second additive may include a siloxane compoundrepresented by the following Chemical Formula 350.

In Chemical Formula 350, R² to R⁵ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom, ahydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxygroup having 1 to 10 carbon atoms, an aminoalkyl group having 1 to 10carbon atoms, an aminoalkoxy group having 1 to 10 carbon atoms, and anaryl group having 6 to 30 carbon atoms; at least any one of R² to R⁵represents an alkoxy group having 1 to 10 carbon atoms, an aminoalkylgroup having 1 to 10 carbon atoms, or an aminoalkoxy group having 1 to10 carbon atoms; and n represents an integer from 1 to 4.

Specifically, the siloxane compound represented by Chemical Formula 350may be any one selected from the group consisting oftris(trimethylsiloxy)silane, tetrakis(trimethylsiloxy)silane,(aminopropyl)tris(trimethylsiloxy)silane,(aminopropyl)tris(diethylaminosiloxy)silane,(aminopropyl)tris(methylethylaminosiloxy)silane,tris(trimethylsiloxy)methylsilane, tris(diethylaminosiloxy)methylsilane,tris(methylethylaminosiloxy)methylsilane, and mixtures thereof.

In the alkoxysilane compound represented by Chemical Formula 300 or thesiloxane compound represented by Chemical Formula 350, the bond betweena silicon atom and an oxygen atom is unstable, and the bond is likely tobe easily broken. However, in a case in which the alkoxysilane compoundrepresented by Chemical Formula 300 or the siloxane compound representedby Chemical Formula 350 contains an amino group, the atomic groupcontaining an amino group can stabilize the bond between a silicon atomand an oxygen atom. That is, the production of reaction side productsthat may be generated as a result of breakage of the unstable bondbetween a silicon atom and an oxygen atom can be minimized. Therefore,the amount of particles produced during the etching process can beminimized, and the defects that may occur in the subsequent processesdue to particles can be minimized.

Furthermore, the oxygen atoms included in the alkoxysilane compoundrepresented by Chemical Formula 300 or the siloxane compound representedby Chemical Formula 350 can be bonded to the surface of an oxide filmand protect the oxide film. For instance, the oxygen atoms included inthe alkoxysilane compound represented by Chemical Formula 300 or thesiloxane compound represented by Chemical Formula 350 form hydrogenbonding with the surface of an oxide film, and thus, an oxide film beingetched while a nitride is being etched can be minimized. Therefore, theetch selectivity for a nitride film with respect to an oxide film can beincreased.

Furthermore, the second additive may include an oxime compoundrepresented by the following Chemical Formula 400. When the compositionfor etching includes the oxime compound represented by Chemical Formula400, the etch rate for a silicon oxide film can be minimized, andsatisfactory etch rate and etch speed for a silicon nitride film can besecured. That is, when a silicon nitride film and a silicon oxide filmlayer exist together, an effect of etching only the silicon nitride filmwhile hardly affecting the silicon oxide film by etching, can beobtained. Furthermore, in the case of using the oxime compoundrepresented by the Chemical Formula 400 together with the alkoxysilanecompound represented by Chemical Formula 300 or the siloxane compoundrepresented by Chemical Formula 350, the solubility of these compoundscan be increased.

In Chemical Formula 400, R¹ and R² each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, acycloalkyl group having 3 to 20 carbon atoms, an aminoalkyl group having1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, analkylcarbonyl group having 1 to 20 carbon atoms, an alkylcarbonyloxygroup having 1 to 20 carbon atoms, and a cyanoalkyl group having 1 to 10carbon atoms.

Specifically, the oxime compound may be any one selected from the groupconsisting of acetone oxime, 2-butanone oxime, acetaldehyde oxime,cyclohexanone oxime, acetophenone oxime, cyclodecanone oxime, andmixtures thereof.

The second additive may include an oxime silane compound represented bythe following Chemical Formula 500. In a case in which the compositionfor etching includes the oxime silane compound represented by ChemicalFormula 500, the etch rate for a silicon oxide film can be minimized,and satisfactory etch rate and etch speed for a silicon nitride film canbe secured. That is, when a silicon nitride film and a silicon oxidefilm layer exist together, an effect of etching only the silicon nitridefilm while hardly affecting the silicon oxide film by etching, can beobtained. Furthermore, high etch rate and etch selectivity can beobtained compared to conventional compositions for etching, and even inthe case of being used for a long time period, there is no problem witha decrease in the etch rate for a silicon nitride film. Thus, thecomposition for etching can be effectively applied at the time ofproducing semiconductor devices for which selective etching of siliconnitride films is needed.

In Chemical Formula 500, R¹ to R³ each independently represent any oneselected from the group consisting of a hydrogen atom, a halogen atom,an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an arylgroup having 6 to 20 carbon atoms, an arylalkyl group having 7 to 20carbon atoms, and an alkylcarbonyl group having 1 to 20 carbon atoms.

More specifically, R¹ to R³ may each independently represent a hydrogenatom, a methyl group, an ethyl group, a n-propyl group, an isopropylgroup, a n-butyl group, a tert-butyl group, a pentyl group, a hexylgroup, a vinyl group, an acetyl group, a benzyl group, or a phenylgroup.

In Chemical Formula 500, R⁴ and R⁵ may each independently represent anyone selected from the group consisting of an alkyl group having 1 to 20carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an arylgroup having 6 to 20 carbon atoms, an arylalkyl group having 7 to 20carbon atoms, and an alkylcarbonyl group having 1 to 20 carbon atoms, orR⁴ and R⁵ may be linked to each other as an alkylene group having 3 to12 carbon atoms and form an alicyclic ring.

More specifically, R⁴ and R⁵ may each independently represent a methylgroup, an ethyl group, a n-propyl group, an isopropyl group, a n-butylgroup, a tert-butyl group, a pentyl group, a hexyl group, a benzylgroup, or a phenyl group, or R⁴ and R⁵ may be fused together and form acyclohexyl group.

In Chemical Formula 500, x, y, and z each independently represent aninteger from 0 to 3, and x+y+z represents an integer from 0 to 3.

Specifically, the oxime silane compound may be any one selected from thegroup consisting of di(ethyl ketoxime)silane, mono(ethy ketoxime)silane,tris(ethyl ketoxime)silane, tetra(ethyl ketoxime)silane, methyltris(methyl ethyl ketoxime)silane, methyl tris(acetoxime)silane, methyltris(methyl isobutyl ketoxime)silane, dimethyl di(methyl ethylketoxime)silane, trimethyl (methyl ethyl ketoxime)silane, tetra(methylethyl ketoxime)silane, tetra(methyl isobutyl ketoxime)silane, vinyltris(methyl ethyl ketoxime)silane, methyl vinyl di(methyl ethylketoxime)silane, vinyl tris(methyl isobutyl ketoxime)silane, and phenyltris(methyl ethyl ketoxime)silane.

Meanwhile, the first inorganic acid is added as an etching agent foretching a nitride film, and any inorganic acid capable of etching anitride film can be used. For example, any one selected from the groupconsisting of sulfuric acid, nitric acid, phosphoric acid, silicic acid,hydrofluoric acid, boric acid, hydrochloric acid, perchloric acid, andmixtures thereof can be used.

Phosphoric acid can be used as the first inorganic acid in order toobtain preferable etch selectivity for a nitride film with respect to anoxide film. This phosphoric acid can play the role of supplying hydrogenions into the composition for etching and thereby accelerating etching.In the case of using phosphoric acid as the first inorganic acid, thecomposition for etching may further include sulfuric acid as anadditive. This sulfuric acid may be helpful in etching of a nitride filmby elevating the boiling point of the composition for etching includingphosphoric acid as the first inorganic acid.

The content of the first inorganic acid may be 70% to 99% by weight,preferably 70% to 90% by weight and more preferably 75% to 85% byweight, with respect to the total weight of the composition for etching.When the first inorganic acid is included at a proportion of less than70% by weight, a nitride film may not be easily removed, and there is arisk that particle generation may occur. When the first inorganic acidis included at a proportion of more than 99% by weight, high selectivityfor a nitride film cannot be obtained.

The composition for etching may include a solvent as the balance of theabove-mentioned components. The solvent may be specifically water,deionized water, or the like.

The composition for etching may further include an ammonium-basedcompound at a proportion of 0.01% to 20% by weight with respect to thetotal amount of the composition for etching. In a case in which thecomposition for etching further includes the ammonium-based compound,even if the composition for etching is used for a long time period, nochange occurs in the etching rate and etch selectivity, and there is aneffect of maintaining the etch rate constant.

When the ammonium-based compound is added in an amount of less than0.01% by weight, the effect of maintaining etch selectivity at the timeof using the composition for etching for a long time period is reduced.When the ammonium-based compound is added in an amount of more than 20%by weight, the etch rates for a nitride film and a silicon oxide filmare changed, and the etch selectivity may be changed.

Regarding the ammonium-based compound, any one selected from an aqueousammonia solution, ammonium chloride, ammonium acetate, ammoniumphosphate, ammonium peroxydisulfate, ammonium sulfate, and ammoniumhydrofluoride, or a mixture of two or more kinds thereof can be used.Furthermore, the ammonium-based compound is not limited to theabove-described compounds, and any compound containing ammonium ion canall be used. For example, as the ammonium-based compound, NH₃ and HClmay be used together.

The composition for etching may further include a fluorine-basedcompound at a proportion of 0.01% to 1% by weight with respect to thetotal amount of the composition for etching. When the fluorine-basedcompound is added in an amount of less than 0.01% by weight, the etchrate for a nitride film is reduced, and the removal of a nitride filmmay become difficult. When the fluorine-based compound is added in anamount of more than 1% by weight, the etch rate for a nitride film issignificantly increased; however, there is a disadvantage that an oxidefilm is also etched.

Regarding the fluorine-based compound, any one selected from hydrogenfluoride, ammonium fluoride, and ammonium hydrogen fluoride, or amixture of two or more kinds thereof can be used. More preferably, it isdesirable to use ammonium hydrogen fluoride because the etch selectivityis maintained upon long-term use.

Meanwhile, the composition for etching may further include any optionaladditives that are conventionally used in the pertinent art in order toenhance the etching performance. Examples of the additives that can beused include a surfactant, a chelating agent, and a corrosion inhibitor.

Since the composition for etching includes the silane inorganic acidsalt described above, the composition for etching can show markedly highetch selectivity for a nitride film with respect to an oxide film, andtherefore, the composition for etching can be used for a nitride filmetching process.

Accordingly, etching of an oxide film can be minimized in an etchingprocess, and thus the EFH can be regulated easily. Furthermore, on theoccasion of etch-selective removal of a nitride film, deterioration ofelectrical characteristics caused by any damage to the film quality ofan oxide film or etching of an oxide film is prevented, and particlegeneration is prevented. Thus, the device characteristics can beenhanced.

A method of manufacturing a semiconductor device according to anotheraspect of the present invention includes an etching process carried outby using the composition for etching described above.

According to an embodiment, such an etching process involves etching ofa nitride film, and more particularly, selective etching of a nitridefilm with respect to an oxide film.

The nitride film may include silicon nitride films, for example, a SiNfilm and a SiON film.

Furthermore, the oxide film may be a silicon oxide film, for example, atleast one or more films selected from the group consisting of aspin-on-dielectric (SOD) film, a high-density plasma (HDP) film, athermal oxide film, a borophosphate silicate glass (BPSG) film, aphosphosilicate glass (PSG) film, a borosilicate glass (BSG) film, apolysilazane (PSZ) film, a fluorinated silicate glass (FSG) film, alow-pressure tetraethyl orthosilicate (LP-TEOS) film, a plasma-enhancedtetraethyl orthosilicate (PETEOS) film, a high temperature oxide (HTO)film, a medium temperature oxide (MTO) film, an undoped silicate glass(USG) film, a spin-on-glass (SOG) film, an advanced planarization layer(APL) film, an atomic layer deposition (ALD) film, a plasma-enhancedoxide (PE-oxide) film, an O3-tetraethyl orthosilicate (O3-TEOS) film,and combinations thereof.

An etching process of using the above-described composition for etchingcan be carried out by any well-known wet etching method, for example, animmersion method or a spraying method.

During the etching process, the process temperature may be adjusted tothe range of 50° C. to 300° C., and preferably 100° C. to 200° C., andthe optimum temperature can be changed as necessary, in consideration ofother processes and other factors.

According to a method of manufacturing a semiconductor device, whichincludes an etching process carried out using the composition foretching described above, in a case in which nitride films and oxidefilms are alternately laminated or exist as a mixture, selective etchingfor nitride films is enabled. Furthermore, particle generation, whichhas been a problem in conventional etching processes, can be prevented,and process stability and reliability can be secured.

Therefore, such a method can be efficiently applied to variousoperations where selective etching for a nitride film with respect to anoxide film is needed, in a semiconductor device production process.

FIG. 3 to FIG. 5 are process cross-sectional views for explaining adevice separation process for a flash memory device, the processincluding an etching process of using the composition for etchingaccording to an embodiment of the present invention.

According to FIG. 3, tunnel oxide film (21), polysilicon film (22),buffer oxide film (23), and pad nitride film (24) are sequentiallyformed on substrate (20).

Subsequently, pad nitride film (24), buffer oxide film (23), polysiliconfilm (22), and tunnel oxide film (21) are selectively etched throughphotolithography and etching processes, and thus, device separationregions of substrate (20) are exposed.

Subsequently, the exposed areas of substrate (20) are selectively etchedusing pad nitride film (24) as a mask, and trenches (25) having apredetermined depth from the surface are formed.

According to FIG. 4, an oxide film (26) is formed over the entiresurface of substrate (20) by using a chemical vapor deposition (CVD)method or the like, until trenches (25) are gap-filled.

Subsequently, a chemical mechanical polishing (CMP) process is performedfor oxide film (26) by using pad nitride film (24) as a polishing stopfilm.

Subsequently, a washing process is performed using dry etching.

According to FIG. 5, pad nitride film (24) is selectively removed by awet etching process of using the composition for etching according tothe present invention, and then buffer oxide film (23) is removed by awashing process. Thereby, device separation film (26A) is formed in thefield region.

As illustrated in FIG. 5, according to the present invention, nitridefilms can be completely and selectively removed for a sufficient timewhile etching of oxide films gap-filled in an STI pattern is minimized,by using a high-selectivity composition for etching having high etchselectivity for a nitride film with respect to an oxide film.Accordingly, the effective oxide film height (EFH) can be easilycontrolled, deterioration of electrical characteristics caused by oxidefilm damage or etching, and particle generation can be prevented, andthe device characteristics can be enhanced.

The embodiments described above have been described with regard to flashmemory devices; however, the high-selectivity composition for etchingaccording to the present invention is also applicable to deviceseparation processes for DRAM devices.

FIG. 6 to FIG. 11 are process cross-sectional views for explaining aprocess for forming channels in a flash memory device, the processincluding an etching process using the composition for etching accordingto another embodiment of the present invention.

According to FIG. 6, pipe gate electrode film (31) having nitride film(32) embedded therein, which is intended for forming pipe channelstherein, is formed on substrate (30). First conductive film (31A) andsecond conducive film (31B) that constitute pipe gate electrode film(31) may contain, for example, polysilicon doped with impurities.

More specifically, first conductive film (31A) is formed on substrate(30), a nitride film is deposited on first conductive film (31A), andthis nitride film is patterned to form nitride film (32) for formingpipe channels. Subsequently, second conductive film (31 b) is formed onfirst conductive film (31A) that is exposed by nitride film (32). Thesefirst conductive film (31A) and second conductive film (31B) constitutepipe gate electrode film (31).

Subsequently, in order to form a plurality of memory cells that arelaminated on the process resultant in a perpendicular direction, firstinterlayer insulating film (33) and first gate electrode film (34) arealternately laminated. Hereinafter, for the convenience of description,the structure obtained by alternately laminating first interlayerinsulating films (33) and first gate electrode films (34) will bereferred to as cell gate structure (CGS).

Here, first interlayer insulating films (33) are intended for separationbetween a plurality of layers of memory cells, and may include, forexample, an oxide film. First gate electrode film (34) may include, forexample, polysilicon doped with impurities. In the present embodiment,six layers of first gate electrode film (34) are shown in the diagram;however, the invention is not intended to be limited this.

Subsequently, the cell gate structure (CGS) is selectively etched, andthereby a pair of first hole and second hole (H1 and H2) that exposenitride film (32) are formed. First hole and second hole (H1 and H2) arespaces for channel formation in memory cells.

According to FIG. 7, nitride film (35) that is embedded in first holeand second hole (H1 and H2) is formed. This nitride film (35) isintended for preventing any damage that may occur when first gateelectrode film (34) is exposed by first hole and second hole (H1 and H2)in the trench forming process (see FIG. 8) that will be described below.

According to FIG. 8, the cell gate structure (CGS) existing between apair of first hole and second hole (H1 and H2) is selectively etched,and thereby trench (S) is formed, so that a plurality of layers of firstgate electrode film (34) are separated into portions corresponding toeach of first hole and second hole (H1 and H2).

According to FIG. 9, sacrificial film (36) that is embedded in thetrench (S) is formed.

According to FIG. 10, second interlayer insulating film (37), secondgate electrode film (38), and second interlayer insulating film (37) aresequentially formed on the process resultant, for the formation of aselection transistor. In the following description, for the convenienceof explanation, a laminated structure of second interlayer insulatingfilm (37), second gate electrode film (38), and second interlayerinsulating film (37) will be referred to as selective gate structure(SGS).

Second interlayer insulating film (37) may contain, for example, anoxide film, and second gate electrode film (38) may contain, forexample, polysilicon doped with impurities.

Subsequently, the selective gate structure (SGS) is selectively etched,and thereby, third hole and fourth hole (H3 and H4) that expose nitridefilm (35) embedded in a pair of first hole and second hole (H1 and H2)are formed. Third hole and fourth hole (H3 and H4) are regions in whichthe channels of a selection transistor will be formed.

According to FIG. 11, nitride film (35) that is exposed by third holeand fourth hole (H3 and H4), and nitride film (32) disposed therebeloware selectively removed by a wet etching process of using thecomposition for etching according to the present invention.

As a result of the present process, a pair of cell channel holes (H5 andH6) in which channel films of the memory cell will be formed; and pipechannel hole (H7) that is disposed below the cell channel holes (H5 andH6) and connects these holes with each other, is formed. At this time,by using the high-selectivity composition for etching according to thepresent invention, nitride films are completely and selectively removedfor a sufficient time without loss of oxide films, and pipe channels canbe accurately formed without loss of the profile. Furthermore, particlegeneration, which has conventionally posed a problem, can be prevented,and the safety and reliability of processes can be secured.

Thereafter, subsequent process, for example, a floating gate formingprocess and a control gate forming process, are carried out, and thus aflash memory device is formed.

FIG. 12 and FIG. 13 are process cross-sectional views for explaining aprocess for forming a diode in a phase change memory device, the processincluding an etching process of using the composition for etchingaccording to another embodiment of the present invention.

According to FIG. 12, an insulating structure having openings, throughwhich conductive region (41) is exposed, is provided on substrate (40).Conductive region (41) may be, for example, an n⁺ impurity region.

Subsequently, polysilicon film (42) is formed so as to embed portions ofthe openings, and then ion implantation of impurities is carried out soas to form a diode.

Subsequently, titanium silicide film (43) is formed on top ofpolysilicon film (42). Titanium silicide film (43) can be formed byforming a titanium film and then heat-treating the titanium film so asto react with polysilicon film (42).

Subsequently, titanium nitride film (44) and nitride film (45) aresequentially formed on top of titanium silicide film (43).

Subsequently, a dry etching process of using a hard mask is carried out,and thereby oxide film (46) is formed in an isolated space between thediodes thus formed. Subsequently, a CMP process is performed, and aprimary structure of lower electrodes that are separated from each otheris formed.

According to FIG. 13, the process resultant is subjected to a wetetching process of using the composition for etching according to thepresent invention, and thus nitride film (45) at the top is selectivelyremoved. As such, a nitride film can be completely and selectivelyremoved for a sufficient time without loss of an oxide film, by usingthe high-selectivity composition for etching according to the presentinvention at the time of removing the nitride film. Furthermore,deterioration of electrical characteristics caused by any damage to thefilm quality of an oxide film and etching of an oxide film, and particlegeneration can be prevented, and the device characteristics can beenhanced.

Subsequently, titanium is deposited in the spaces where nitride film(45) has been removed, and thus lower electrodes are formed.

In addition to the processes described above, a method of manufacturinga semiconductor device, which includes an etching process carried outusing the composition for etching of the present invention, can beefficiently applied particularly to a process where selective removal ofa nitride film is required, for example, a process where selectiveetching for a nitride film is required in a case in which nitride filmsand oxide films are alternately laminated or exist as a mixture.

MODE FOR INVENTION

Hereinafter, Examples of the present invention will be described indetail so that those having ordinary skill in the art to which thepresent invention is pertained can easily carry out the invention.However, the present invention can be realized in various differentforms and is not intended to be limited to the Examples describedherein.

Production Example: Production of Silane Inorganic Acid Salt

Silane inorganic acid salts were produced as disclosed in the followingTable 1.

TABLE 1 Weight Pro- ratio of duc- second tion inorganic Reaction Ex-Second acid temper- am- inorganic and silane ature ple Silane compoundacid compound (° C.) A1 Compound represented Phosphoric 20:100 70 byChemical Formula 10, acid in which R¹ is a methyl group; and R² to R⁴are each a chloro group. A2 Compound represented Sulfuric acid 10:100 70by Chemical Formula 10, in which R¹ is a methyl group; and R² to R⁴ areeach a chloro group. A3 Compound represented Nitric acid 10:100 50 byChemical Formula 10, in which R¹ is a methyl group; and R² to R⁴ areeach a chloro group. B1 Compound represented Pyrophosphoric 10:100 70 byChemical Formula 10, acid in which R¹ is a methyl group; and R² to R⁴are each a chloro group. B2 Compound represented Polyphosphoric 20:10070 by Chemical Formula 10, acid in which R¹ is a methyl (includinggroup; and R² to R⁴ are three each a chloro group. phosphorus atoms) C1Compound represented Phosphoric acid 50:100 90 by Chemical Formula 20,in which R⁶ to R⁹ are each a chloro group; R⁵ and R¹⁰ are each a methylgroup; and n is 1. C2 Compound represented Pyrophosphoric 50:100 90 byChemical Formula 20, acid in which R⁶ to R⁹ are each a chloro group; R⁵and R¹⁰ are each a methyl group; and n is 1. C3 Compound representedSulfuric acid 40:100 120 by Chemical Formula 20, in which R⁶ to R⁹ areeach a chloro group; R⁵ and R¹⁰ are each a methyl group; and n is 1. C4Compound represented Nitric acid 50:100 150 by Chemical Formula 20, inwhich R⁶ to R⁹ are each a chloro group; R⁵ and R¹⁰ are each a methylgroup; and n is 1. C5 Compound represented by Polyphosphoric 50:100 150Chemical Formula 20, acid in which R⁶ to R⁹ are each (including a chlorogroup; R⁵ and three R¹⁰ are each a methyl phosphorus group; and n is 1.atoms)

Reference Example: Production of Composition for Etching

As shown in the following Table 2, compositions for etching wereproduced by mixing the compound indicated in the following Table 2 as asecond additive, and phosphoric acid as a first inorganic acid, at theweight ratios indicated in the table with respect to the total weight ofthe composition, without incorporating a first additive. For the firstinorganic acid, a 85% aqueous solution was used.

TABLE 2 First inorganic Second additive acid (wt %) (wt %) ReferencePhosphoric Compound produced in Example 1-1 acid (balance) ProductionExample A1 (1.0) Reference Phosphoric Compound produced in Example 1-2acid (balance) Production Example B1 (0.5) Reference Phosphoric Compoundproduced in Example 1-3 acid (balance) Production Example C1 (1.0)Reference Phosphoric Aminopropylsilanetriol (1.2) Example 1-4 acid(balance) Reference Phosphoric(Aminopropyl)tris(diethylaminosiloxy)silane Example 1-5 acid (balance)(0.1) Reference Phosphoric (Aminopropyl)tris(diethylaminosiloxy)silaneExample 1-6 acid (balance) (0.1) + acetone oxime (1.0) ReferencePhosphoric Methyl tris(methyl ethyl ketoxime)silane Example 1-7 acid(balance) (0.1)

Experiment Example 1: Measurement of Selectivity of Composition forEtching Thus Produced

Etching for a nitride film and an oxide film at a process temperature of157° C. was performed using the compositions for etching produced in theReference Examples described above, and the etch rate and selectivityfor a nitride film and an oxide film were measured using an ellipsometer(NANOVIEW, SEMG-1000), which is a thin film thickness measuringapparatus. The etch rates and selectivity values are presented in Table3. The etch rate is a value obtained by etching a film for 300 seconds,and subsequently measuring the film thickness before the etchingtreatment and the film thickness after the etching treatment, anddividing the difference of the film thicknesses by the etching time(minutes), and the selectivity represents the ratio of the etch rate fora nitride film with respect to the etch rate for an oxide film.

Meanwhile, in Comparative Example 1, the etch rate and the selectivitywere measured as described above at a process temperature of 157° C.using phosphoric acid. In Comparative Example 2, the etch rate and theselectivity were measured at a process temperature of 130° C., which isa low process temperature applicable to a process where hydrofluoricacid is added, using a mixture obtained by adding 0.05% of hydrofluoricacid to phosphoric acid. In Comparative Example 3, the etch rate and theselectivity were measured at a process temperature of 157° C., which isthe same temperature as that employed in Examples, using the samemixture as that used in Comparative Example 2. The phosphoric acid usedin Comparative Examples 1 to 3 was a 85% aqueous solution. Theevaluation results for Comparative Examples 1 to 3 are also presented inthe following Table 3.

TABLE 3 Oxide film Process Nitride etch rate temper- film (Å/min)Selectivity ature etch rate LP- LP- (° C.) (Å/min) ThO_(x) ¹⁾ TEOS²⁾ThO_(x) ¹⁾ TEOS²⁾ Comparative 157 65.02 1.20 3.26 54.18 19.94 Example 1Comparative 130 18.23 0.00 0.03 — 607.67 Example 2 Comparative 157 78.696.56 8.26 12.00 9.53 Example 3 Reference 157 65.26 0.10 0.13 652.60502.00 Example 1-1 Reference 157 64.29 0.05 0.07 1285.80 918.43 Example1-2 Reference 157 65.01 0.08 0.11 812.63 591.00 Example 1-3 Reference157 64.89 0.07 0.10 927.00 648.90 Example 1-4 Reference 157 64.56 0.060.10 1076.00 645.60 Example 1-5 Reference 157 63.05 0.09 0.16 700.56394.06 Example 1-6 Reference 157 65.36 0.10 0.13 653.60 502.77 Example1-7 ¹⁾ThO: Thermal oxide film ²⁾LP-TEOS: Low pressure tetraethylorthosilicate film

According to Table 3, it can be confirmed that the compositions foretching of Reference Examples have noticeably high etch selectivity fora nitride film with respect to an oxide film, compared to ComparativeExamples 1 to 3. Therefore, when the compositions for etching accordingto Reference Examples are used, the EFH can be easily regulated byregulating the etch rate for an oxide film, and any damage to the filmquality of an oxide film can be prevented. Furthermore, particlegeneration, which has conventionally posed a problem, can be prevented,and the stability and reliability of processes can be secured.

Meanwhile, in order to simulate an actual high-temperature phosphoricacid process, a preliminary operation of arbitrarily dissolving asilicon nitride film in the compositions for etching produced asdescribed above and increasing the silicon concentration in thesolution, was carried out. At the time of performing the process, as thesilicon nitride film is etched, the silicon concentration in thesolution increases, and thereby, the etch rate for a silicon oxide filmis further decreased. The preliminary operation was carried out untilthe silicon concentration in the solution reached 100 ppm, and thenetching was performed. The results are presented in the following Table4.

TABLE 4 Oxide film Process Nitride etch rate temper- film (Å/min)Selectivity ature etch rate LP- LP- (° C.) (Å/min) ThO_(x) TEOS ThO_(x)TEOS Reference 157 65.35 0.01 0.01  6535.00 6535.00 Example 1-1Reference 157 64.10 −0.04 0.02 −1602.50 3205.00 Example 1-2 Reference157 64.56 −0.01 0.00 −6456.00 — Example 1-3 Reference 157 64.52 0.000.03 — 2150.67 Example 1-4 Reference 157 64.71 −0.02 0.02 −3235.503235.50 Example 1-5 Reference 157 64.23 −0.01 0.01 −6423.00 6423.00Example 1-6 Reference 157 64.67 −0.03 −0.01 −2155.67 −6467.00  Example1-7

According to Table 3 and Table 4 given above, it can be seen that at thetime of simulating an actual high-temperature phosphoric acid process,the selectivity of the Reference Examples is noticeably decreased. Thisis because when the silicon concentration in the solution increases asin the case of an actual process, a silicon oxide film is not etched,but the thickness of the silicon oxide film rather increases.

Example: Production of Composition for Etching

As shown in the following Table 5, compounds indicated in the followingTable 5 as first additives, compounds indicated in the following Table 5as second additives, and phosphoric acid as a first inorganic acid weremixed at the various weight ratios indicated with respect to the totalweight of the composition, and thus compositions for etching wereproduced. Regarding the first inorganic acid, a 85% aqueous solution wasused.

TABLE 5 First inorganic First additive Second additive acid (wt %) (wt%) (wt %) Example Phosphoric Phosphorous Compound produced in 1-1 acidacid (1) Production Example A1 (balance) (1.0) Example PhosphoricPhosphorous Compound produced in 1-2 acid acid (3) Production Example B1(balance) (0.5) Example Phosphoric Phosphorous Compound produced in 1-3acid acid (7) Production Example C1 (balance) (1.0) Example PhosphoricPhosphorous Aminopropylsilanetriol (1.2) 1-4 acid acid (3) (balance)Example Phosphoric Phosphorous (Aminopropyl)tris(diethylamino- 1-5 acidacid (5) siloxy)silane (0.1) (balance) Example Phosphoric Phosphorous(Aminopropyl)tris(diethylamino- 1-6 acid acid (10) siloxy)silane (0.1) +(balance) acetone oxime (1.0) Example Phosphoric Phosphorous Methyltris(methyl ethyl 1-7 acid acid (5) ketoxime)silane (0.1) (balance)Example Phosphoric Dimethyl Compound produced in 2-1 acid phosphite (3)Production Example A1 (balance) (1.0) Example Phosphoric DimethylCompound produced in 2-2 acid phosphite (5) Production Example B1(balance) (0.5) Example Phosphoric Dimethyl Compound produced in 2-3acid phosphite (7) Production Example C1 (balance) (1.0) ExamplePhosphoric Dimethyl Aminopropylsilanetriol (1.2) 2-4 acid phosphite (7)(balance) Example Phosphoric Dimethyl (Aminopropyl)tris(diethylamino-2-5 acid phosphite (10) siloxy)silane (0.1) (balance) Example PhosphoricDimethyl (Aminopropyl)tris(diethylamino- 2-6 acid phosphite (5)siloxy)silane (0.1) + (balance) acetone oxime (1.0) Example PhosphoricDimethyl Methyl tris(methyl ethyl 2-7 acid phosphite (5) ketoxime)silane(0.1) (balance) Example Phosphoric Ammonium Compound produced in 3-1acid hypophosphite Production Example A1 (balance) (5) (1.0) ExamplePhosphoric Ammonium Compound produced in 3-2 acid hypophosphiteProduction Example B1 (balance) (3) (0.5) Example Phosphoric AmmoniumCompound produced in 3-3 acid hypophosphite Production Example C1(balance) (7) (1.0) Example Phosphoric Ammonium Aminopropylsilanetriol(1.2) 3-4 acid hypophosphite (balance) (4) Example Phosphoric Ammonium(Aminopropyl)tris(diethylamino- 3-5 acid hypophosphite siloxy)silane(0.1) (balance) (5) Example Phosphoric Ammonium(Aminopropyl)tris(diethylamino- 3-6 acid hypophosphite siloxy)silane(0.1) + (balance) (3) acetone oxime (1.0) Example Phosphoric AmmoniumMethyl tris(methyl ethyl 3-7 acid hypophosphite ketoxime)silane (0.1)(balance) (5)

Experiment Example 2: Measurement of Selectivity of Composition forEtching Produced

For the compositions for etching produced in Examples described above,an actual high-temperature phosphoric acid process was simulated asdescribed above, and then etching for a nitride film and an oxide filmwas performed at a process temperature of 157° C. The etch rates andselectivity for a nitride film and an oxide film were measured using anellipsometer (NANOVIEW, SEMG-1000), which is a thin film thicknessmeasuring apparatus. The etch rates and selectivity are presented inTable 6.

TABLE 6 Oxide film Process Nitride etch rate temper- film (Å/min)Selectivity ature etch rate LP- LP- (° C.) (Å/min) ThO_(x) TEOS ThO_(x)TEOS Example 1-1 157 65.35 0.05 0.08 1307.00 816.88 Example 1-2 15764.10 0.03 0.06 2136.67 1068.33 Example 1-3 157 64.56 0.06 0.06 1076.001076.00 Example 1-4 157 64.52 0.03 0.06 2150.67 1075.33 Example 1-5 15764.71 0.03 0.05 2157.00 1294.20 Example 1-6 157 64.23 0.05 0.12 1284.60535.25 Example 1-7 157 64.67 0.06 0.08 1077.83 808.38 Example 2-1 15765.35 0.06 0.10 1089.17 653.50 Example 2-2 157 64.10 0.03 0.03 2136.672136.67 Example 2-3 157 64.56 0.06 0.06 1076.00 1076.00 Example 2-4 15764.52 0.06 0.07 1075.33 921.71 Example 2-5 157 64.71 0.04 0.07 1617.75924.43 Example 2-6 157 64.23 0.05 0.10 1284.60 642.30 Example 2-7 15764.67 0.07 0.08 923.86 808.38 Example 3-1 157 65.35 0.05 0.08 1307.00816.88 Example 3-2 157 64.10 0.03 0.02 2136.67 3205.00 Example 3-3 15764.56 0.07 0.07 922.29 922.29 Example 3-4 157 64.52 0.05 0.06 1290.401075.33 Example 3-5 157 64.71 0.03 0.06 2157.00 1078.50 Example 3-6 15764.23 0.06 0.11 1070.50 583.91 Example 3-7 157 64.67 0.06 0.09 1077.83718.56

According to Table 6, it can be confirmed that the compositions foretching of Examples show significantly high etch selectivity for anitride film with respect to an oxide film even at the time ofsimulating an actual high-temperature phosphoric acid process, byfurther containing the first additive.

The present invention is not intended to be limited by the embodimentsdescribed above and the attached drawings, and it will be obvious tothose having ordinary skill in the art to which the present invention ispertained, that various replacements, alterations, and modifications canbe made to the extent that the technical idea of the present inventionis maintained.

[List of Reference Numerals] 20, 30, 40: Substrate 21: Tunnel oxide film22: Polysilicon film 23: Buffer oxide film 24: Pad nitride film 25:Trench 26: Oxide film 26A: Device separation film 31: Pipe gateelectrode film 32, 35: Nitride film 36: Sacrificial film 33: Firstinterlayer insulating film 34: First gate electrode film 37: Secondinterlayer insulating film 38: Second gate electrode film 41: Conductionregion 42: Polysilicon film 43: Titanium silicide film 44: Titaniumnitride film 45: Nitride film 46: Oxide film

INDUSTRIAL APPLICABILITY

The present invention relates to a composition for etching and a methodof manufacturing a semiconductor device, the method including an etchingprocess using the composition for etching. The composition for etchingis a high-selectivity composition for etching that can selectivelyremove a nitride film while minimizing the etch rate for an oxide filmand does not have problems such as particle generation, which adverselyaffect the device characteristics.

The invention claimed is:
 1. A method for forming a cell gate structure,the method comprising: forming a cell gate structure on a substrate byalternatively stacking a plurality of interlayer insulating layers and aplurality of gate electrode layers; forming a plurality of holes throughthe cell gate structure; and selectively etching a plurality of nitridelayers in the cell gate structure by a composition, wherein thecomposition for the selective etching comprises: a first inorganic acid,a first additive, being any one selected from the group consisting ofphosphorous acid, an organic phosphite, a hypophosphite, and mixturesthereof, a second additive comprising a silane inorganic acid saltproduced by reaction between a second inorganic acid and a silanecompound; and a solvent, wherein: the second inorganic acid is at leastone selected from the group consisting of a phosphoric acid, ananhydrous phosphoric acid, a pyrophosphoric acid, a polyphosphoric acid,and a combination thereof; and the silane compound is a compoundselected from Chemical Formulas A10, A20, and their combination, thesilane inorganic acid salt is represented by Chemical Formula C200-1,wherein the composition for etching comprises the first additive at aproportion of 0.01% to 15% by weight, the first inorganic acid at aproportion of 70% to 99% by weight, the second additive at a proportionof 0.01% to 20% by weight, and the solvent as the balance,

(In Chemical Formula A10 and Chemical Formula A20, each R¹ to R¹⁰ isindependently selected from the group consisting of hydrogen, halogen,(C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀) aryl, at least one of R¹to R⁴ is hydrogen, or (C₁-C₁₀) alkoxy, and n is one of integer numbersfrom 1 to 10,)

(In Chemical Formula C200-1, each R¹¹¹ to R¹¹² is independently selectedfrom the group consisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀)alkoxy, and (C₆-C₃₀) aryl, each R¹¹³ to R¹²² is independently hydrogen,each o₁, o₂₁, o₂₂ and o₃ is independently one of integer numbers from 0to 10, n₄ is one of integer numbers from 0 to 2, li is one of integernumbers from 0 to 10, m₁ is 0 or 1).
 2. The method of claim 1, whereinany one of hydrogen of R¹¹³ to R¹²² in the Chemical Formula C200-1 issubstituted by Chemical Formula C220-1,

(In Chemical Formula C220-1, any one of R¹³¹ to R¹³² is a couplercoupling to Chemical Formula C200-1, the other is independently selectedfrom the group consisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀)alkoxy, and (C₆-C₃₀) aryl, and each R¹¹³ to R¹²² is independentlyhydrogen, or substituted by a substituent represented by ChemicalFormula C220-1, and each o₁, o₂₁, o₂₂ and o₃ is independently one ofinteger numbers from 0 to 10, n₄ is one of integer numbers from 0 to 2,1₁ is one of integer numbers from 0 to 10, m₁ is 0 or 1).
 3. The methodof claim 1, wherein the silane inorganic acid salt represented byChemical Formula C200-1 is any one selected from the group consisting ofChemical Formulas 52, 53, 55, 56, 57, 103, 106, 107, 108, 205, 207, 208,209, 210, and their combination,

(In Chemical Formulas 52, 53, 55, 56, 57, 103, 106, 107, 108, 205, 207,208, 209 and 210, each R¹, R², R¹⁻¹, R¹⁻², R¹⁻³, R¹⁻⁴, R¹⁻⁵, R¹⁻⁶, R¹⁻⁷,R¹⁻⁸, R²⁻¹, R²⁻², R³⁻¹, R³⁻², and R³⁻³ is independently selected fromthe group consisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀)alkoxy, and (C₆-C₃₀) aryl).